Experimental Study on Steel–Concrete Composite Twin I-Girder Bridges

Abstract

A large number of steel-concrete composite twin I-girder bridges have been built in both Europe and Japan, but the lack of redundancy has always been a concern in the U.S. and many other countries. In addition, very few experimental studies have been performed on mechanical performance of such bridges, particularly for the intact twin I-girder bridges. On this background, a steel-concrete composite twin I-girder bridge specimen was designed according to the current highway bridge design specification in Japan. The static loading tests were performed, and two loading conditions including both symmetric loading and asymmetric loading were applied. Load versus deflection relationship and strain development on steel main girders and concrete slab at key sections were measured. The flexural strains on the lateral beam were also measured and reported in this paper to confirm the load transfer between two main girders. In addition, the shear strain of shear connectors (stud, in this study) was also measured to investigate the shear force transmission on the steel-concrete interface. The theoretical values were also provided to compare with the test results from the twin girder specimen under symmetric loading condition. The experimental results indicate that the theoretical analysis can predict the behavior of the twin-girders very well in the elastic stage by considering the effective width of the slab. Performance of each structural components and load transfer paths in such bridges were also discussed.

Effect of Cross-Frames on Load Distribution of Steel Bridges with Fractured Girder

“…Recent studies on the reserved capacity of bridges and redundancy evaluation have mainly focused on the steel I-girder and box-girder bridges with a partial or full-depth fracture of one of the girders [14][15][16][17][18][19][20][21][22][23][24][25]. The results of these studies demonstrated a high level of internal redundancy and secondary load paths in the bridge systems.…”

Cracking control technique for continuous steel-concrete composite girders under negative bending moment

“…However, near the middle pier of the continuous steel-concrete composite girder, the hogging moment violates this law. It subjects the upper concrete deck slab to tension and the bottom steel beam to compression [11][12][13]. Under the hogging moment, the concrete deck with low tensile strength would inevitably crack and bring poor durability and low safety margin, making the deck slab at the region easy to deteriorate during the bridge operation [14].…”